This disclosure relates to anchor windings for various electro-mechanical machines of small and medium size, for example automobile generators, electrical DC and AC motors both round, arc and linear for driving various equipment, etc. in which windings are placed in slots of an iron core. There are numerous disadvantages of prior designs, namely, the majority of windings for small and medium size electrical machines are manufactured using round wire which is not capable of providing highly uniform winding, causes high electrical losses, low copper fill in slots and requires complex and labor consuming operations while being manufactured.
Other prior designs describe various designs for stators of electrical machines, mostly automotive generators, formed of rectangular or square cross sectional wire. Such wire can be laced into the stator core winding slots in a very densely packed configuration. This allows larger cross sectional areas to be provided for the conductors, thus lowering the winding's resistance. Reducing the stator core winding resistance improves efficiency. Such rectangular wire core designs are said to improve “slot space utilization”.
Further other designs describe a stator winding which includes a plurality of U-shaped segment conductors and forms two coil ends which project from two end surfaces of the stator iron core in axial directions respectively, the segment conductors including U-shaped turn portions respectively. The U-shaped turn portions are located in one of the two coil ends, and ends of the segment conductors are located in the other of the two coil ends; wherein the ends of the segment conductors are connected at joint portions which are arranged in a multiple-ring shape.
Still further prior designs describe rectangular conductors placed in stator slots, in particular each of electric conductors which are accommodated in one of slots and are adjacent to one another are bent. This invention includes not less than four conductors per slot, stacked only in a radial direction.
Another prior design describes the main difference being that the stator has two end surfaces, in an axial direction of said iron core, which are formed such that one of the two end surfaces has openings constituting second slot openings through which said electric conductors are inserted into said slots, end portions of said electric conductors being bent in circumferential directions at positions immediately outward of said second openings.
Yet other prior designs describe variants of technology having conductors with square or rectangular cross section in slots and round in the front end zones.
Still yet other designs describe multi-phase stator winding, comprised of independent sets of three-phase windings, each being wound on the armature core by being inserted in the slots so that the n sets of three-phase windings are shifted from each other by an electrical angle of π/(3n) radians. Also, a design is described comprised of first and second sets of three-phase windings wound respectively being inserted in said plurality of slots so that the respective sets of three-phase windings are arranged with a phase difference of electrical angle of π/6 radians therebetween;
Further prior designs describe similar solutions based on utilization of U-shaped segments for multi-phase stator winding. In particular, different layers arranged in a depth direction of each slot, and conductor segments are insulated from each other. This multi-phase stator is suggested for use together with a Lundel-type rotor.
Yet other prior designs describe utilization of the given design to achieve good air cooling for the stator using in front end zones a cooling air passageway; two ventilation passages are provided at both axial ends of the field rotor.
Still yet other prior designs describe various technologies for manufacturing windings with square or rectangular conductors.
Other prior designs describe the method of welding a plurality of pairs of connection ends of a plurality of segments of a circumferentially disposed stator winding of a rotary electric machine.
Further other prior designs describe a design and method for manufacturing a winding in which two continuous electrical conductors per phase are positioned into a predetermined pitch of the winding slots, and extend from the lead side and non-lead side of the core.
A major disadvantage of the above design and method of manufacturing is the requirement to make many welding connections—two connections per slot for two-layer winding and four connections per slot for four-layer winding. These connections have to be made in a very limited space making manufacturing labor consuming and expensive.
Moreover other prior designs describe a stator having a polyphase stator winding comprising a number of winding sub-portions in each of which a long strand of wire is wound so as to alternately occupy an inner layer and an outer layer in a slot depth direction within said slots at intervals of a predetermined number of slots, the strand of wire folding back outside the slots at axial end surfaces of the stator core, wherein winding subportions are constituted by at least one winding assembly.
These designs reduce the amount of necessary welding, however at the expense of a more complicated process of stator manufacturing.
Therefore, there is a need in the art for a method for manufacturing armature windings for electro-mechanical machines that overcomes the disadvantages of the prior art, provides highly uniform winding, increased copper fill in slots, improved motor efficiency, lower material costs and labor consumption for manufacturing and provides the opportunity for automated production.